Technical Field
The present application relates generally to bore inspection systems and more particularly to bore imaging systems.
Description of the Related Art
Various bore imaging systems are known that use a bore surface imaging arrangement for imaging the interior of a bore, for example in a cylinder bore of an engine. Exemplary bore inspection systems are disclosed in U.S. Pat. Nos. 4,849,626 (the '626 patent); 7,636,204 (the '204 patent); 8,334,971 (the '971 patent); 8,570,505 (the '505 patent); and U.S. Patent Application No. 2013/0112881, each of which is hereby incorporated herein by reference in its entirety. Such bore imaging systems may be configured to provide a 360 degree view (also referred to as a panoramic view and/or image) of the interior of a bore in order to inspect for form errors or surface defects. Some such systems use high-resolution optics. In any case, such systems may use signal processing to map image pixel signals or detector element signals to coordinates within the interior of the bore. In some such systems, a panoramic image of an approximately annular portion of a bore may be projected onto a two-dimensional (2-D) rectangular imaging array in a circular pattern corresponding to the shape of the annular portion. The circular or annular image pixels may then span a relatively large set of pixels (e.g., most of the rectangular imaging array) while actually imaging onto only a relatively small proportion of that set of pixels (e.g., an annular image pattern within the rectangular imaging array). A typical imaging array must read out each pixel spanned by the circular or annular bore image, even though pixels outside of the annular image pattern (e.g., interior and exterior to it) are not relevant to inspection of the bore. Additionally, such systems may have to utilize image mapping computation to map pixels from the annular image pattern to the surface of the bore. Continuously reading out irrelevant pixels and mapping relevant pixels takes time, which limits the speed with which such a bore imaging system may be used to inspect a bore. Some systems (e.g., as disclosed in the '626 patent) have used fiber optic imaging paths, and routed each fiber to a corresponding photodetector. However, configurations of such systems have also imposed speed limitations, as well as imaging limitations that have limited resolution and/or versatility with regard to the range of bore sizes that may be inspected using a given system.
A high-speed, high-resolution, metrology grade bore imaging system which solves the problems outlined above would be desirable.